This present invention leverages several technology fields for the design of a novel mobile network, like IT (information technology) connectivity principles, telco (telecommunication) transport, mobile network architecture, cloud computing and software defined network. Therefore, each of the fields shall be shortly strived with respect to its relevance for this present invention.
IT End-to-End Networking Principles
Today, IT networks comprise a set of interconnected access networks, commonly named local area networks (LAN), where connectivity is mainly based on layer 2 Ethernet. FIG. 1 shows an example of an IT network, where hosts (HA, HB) are connected to the LAN either by wire (see right part of FIG. 1) or wirelessly (left part) via a Wireless LAN (WLAN) access point. Those hosts may consist of e.g. a notebook with some application running on it, e.g. a web browser fetching content by use of the HTTP protocol, or a server running a web server to provide content by supporting the HTTP protocol. The applications on hosts communicate with servers, which are connected as peer hosts to the same or a separate LAN following the same connection principles. Host to host communication is based on layer 3 functionalities, commonly the Internet Protocol and IP addresses.
Since the range of a layer 2 network (LAN) is typically limited to a couple of thousand hosts, the interconnection between larger networks, i.e. various LANs is based on forwarding according to layer 3 IP addresses. Host IP addresses have a network wide significance. In order to guarantee proper assignment of IP addresses to hosts and in order to forward data packets from one LAN (layer 2 addressing) via a routed network (layer 3 addressing, see middle of FIG. 1) to another LAN (layer 2 addressing) to the peer host, access routers are placed at each LAN's edge to forward packets between LANs based on IP addresses.
The access router's main tasks (with respect to this present invention) comprise of (I) intercept packets with locally unique IP addresses of hosts that attach to this LAN addressed to IP addresses falling outside of the local address range, and (II) to forward those packets to the access router, which takes care of the local IP addresses of the peer host, which is located in a different LAN. Consequently, packets received from peer hosts to host attached to the LAN as recipient, are interworked in the reverse order.
Intra LAN communication is solely done based on layer 2 forwarding, deploying Ethernet MAC addresses for identification of the end station (see bottom of FIG. 1) and using IEEE 802.3 Ethernet, or IEEE 802.11 in case of wireless LAN links, for the physical transport. The layer 1 and layer 2 tunneling of long haul connections between the LANs may be based on various (also non-Ethernet) technologies including optical transport, indicated by link layer control LLC and physical layer PHY.
While layer 2 forwarding is used for communication between stations within a LAN, layer 3 (IP) is used for forwarding/routing between the peer hosts potentially traversing multiple LANs.
In an access router, typically a DHCP (Dynamic Host Configuration Protocol) server function will assign local IP addresses to hosts which are connecting to it.
When the DHCP server located in the access router assigns an IP address to a host, it will also provide a network mask that indicates the range of IP addresses that are used in this local area network. This allows a host to distinguish whether or not a peer host is in the same LAN or not.
Fixed and Mobile (Telco) End-to-End Networks
FIG. 2 shows the basic architecture of a mobile network. In a simplified view, a mobile network comprises of five domains:                User Equipment UE. Those may range from simple cellular mobile phones over smart phones to wireless notebooks;        Radio Access Network RAN comprising of base stations, antennas, everything that is there to provide radio access;        Mobile Core. This includes facilities necessary to handle user authentication and authorization, where user subscription data is stored (HSS home subscriber system);        Service Delivery Framework SDF. This comprises of servers for mobile operator content and services including content delivery functions like cashing;        Backend System. Here are the network management facilities and billing and charging systems.        
In addition, there are two edges—between RAN and core and between core and world wide services networks.
The RAN/core edge comprises of facilities which are mobile network generation dependent, i.e. in a 2G network (GSM) those comprise of base station controllers BSC which control bundles of base stations (e.g. for paging), in case of 3G (UMTS) those are radio network controllers RNC with much more complexity (terminating parts of the radio layer, performing soft combining). In a 4G network (LTE) there is no edge function since the function split again changed significantly with packet based (IP or Ethernet) connections from base station to the core and all radio layers terminated in the base station (eNodeB) and with mobility management moving to the core network into Mobility Management Entity MME.
The core/services networks edge comprises of entities which handle the communication between the mobile network and the outside world. Mobile Switching Centers MSC handle narrowband circuit switched voice traffic (and MSC-Servers and media gateways Voice-over-IP based communication, not shown in FIG. 2). Packet data access to/from services networks (internet) is handled by a GPRS Gateway Serving Node GGSN or by a Servicing/Packet Gateway S/P-Gw in case of 4G LTE.
Edge nodes like RNC or GGSN are unique points in the network since all traffic (at least all packet data traffic, i.e. all internet traffic) runs through them. Due to their complexity their numbers are limited per network so that there are a few crucial topological points in the network which are single points of failure and which may become performance bottlenecks as traffic increases significantly (200 times in 10 years).
According to this simplified architecture, a broadband fixed network architecture can be drawn alike (no shown). Here the Access Network can have a DSL Access Multiplexer DSLAM as an edge node (which terminates the physical layer towards the DSL modems) and a Broadband Remote Access Server BRAS as a core/services network edge node.
Network Virtualization, Virtual Machines, Cloud Computing
A major trend in telecommunications, also in mobile networks, especially in the core is to use data center technologies for running applications. One motivation of that is to reduce TCO (total cost of ownership) since one platform (data center) can be used for many (most) applications that by today are often running on distinct network nodes. Furthermore, it allows a better scaling and more elasticity since applications can be invoked and terminated flexibly according to networking demands. FIG. 3 shows a typical setup of a data center and its management entities.
The data center itself comprises of hardware including multi core processing units and switching facilities (D-Switch in FIG. 3) to interconnect different processing units on the multiple blades in the multiple racks that make up a data center. The multiple computing parts will be equipped with an operating system (host OS, e.g. Linux) on which one or several virtual machines VM can be established. These VMs may be equipped with application software running on top of yet another operating system (guest OS, e.g. Linux, Windows). The control of the different VMs is done by a piece of HiperVisor HV middleware which acts as a mediator between the guest OS/VM and the host operating system hiding the virtual nature of the platform to the guest OS.
Virtual machines will be invoked/terminated and equipped with software images by an Infrastructure-as-a-service (IaaS) component, also denoted as Cloud Management System. On demand (of e.g. a cloud orchestration system) a specific software image (which may also include the guest OS) out of a list of software images that is stored in a database will be started on a virtual machine. The selection of the VM is done and controlled by this entity.
The Cloud Orchestration Function, e.g. NSN Cloud Application Manager CAM, stores templates for specific software that shall be deployed in a network which are stored in yet another database. Those templates comprise e.g. of information about how many applications make up a network function (e.g. three applications together form a voice communication server VCS), which of the images that are stored in the IaaS database do reflect this application(s), the starting order of the different applications, IDs that allow to identify running applications and more. Per screen level command or triggered by an external network control (e.g. via http based interface) or by an orchestrator as defined in ETSI NFV (European Telecommunications Standards Institute Network Functions Virtualization) new applications can be started/stopped/modified and monitored. The Cloud Orchestration System will communicate with the IaaS or cloud management system, respectively, and directly/indirectly with the application. Yet those interfaces are still subject of standardization, current solutions employ Quantum, OpenStack and Eucalyptus and derivates of those.
Software Defined Networks—SDN Transport
Another trend is gaining momentum in CSP networks, SDN—the decoupling of data forwarding and control.
By today, typical nodes in transport networks comprise of specific functionalities. A router, for example, comprises of data switching functionalities which move data packets between the different I/O ports. But it also handles all the complex routing protocols like RSVP (resource reservation protocol), it holds routing tables and more. All the complex functionality and the switching are encapsulated in one box.
Another example would be a carrier Ethernet switch, providing data forwarding and control on layer 2. And more and more multilayer switches are used in transport networks providing MPLS (multi protocol label switching) functionality which on top of the before mentioned router or switch functionality provide MPLS/G-MPLS signaling capability. Bottom line, depending for what purpose a transport node is used, it is more or less complex providing data forwarding and control function in one monolithic node.
The basic idea of SDN is to decouple control functions from data forwarding functions, in other words, everything that makes a router being a router and everything that makes a switch being a switch is taken out of a node, let's call it network element NE and put it into a controller. What will be remaining in the NE is pure data forwarding functionality. With this philosophy, routers, switches, MPLS nodes would all have a similar look-alike NE for data forwarding, and a specific control element (which is outside the box) which makes it a router or a switch or whatsoever.
FIG. 4 illustrates the principles of SDN.
At the bottom of FIG. 4, a NE providing pure data forwarding functionality is shown. It comprises of the switching hardware (data path) which provides I/O ports, some pieces of software to allow configuration, a flow table which contains port based rules for data forwarding. Here will be a description of how to handle a packet depending on e.g. header information. For example, a rule may be that incoming packets on port 0 will be analyzed such that depending what information is in the header, the packet shall be forwarded to port 2 or 3. These rules, which are stored in a flow table, can be passed to the NE from a controller which resides out of the box (denoted as SDN control). For that, a protocol for exchange must be specified and both, the controller and the NE must be able to mutually understand the protocol (SDN client). A most prominent representative for an SDN control protocol is OpenFlow as specified in the Open Network Foundation ONF. Another known representative is Forces.
This way and with additional means a whole eco system for sharing transport equipment can be built up. NEs and controller can be cascaded and access can be limited. Introducing FlowVisors will limit access to certain parts of a Flow Table (e.g. ports 0 to 3). Controllers themselves may act as proxies to other controllers. Finally, SDN controllers may provide a northbound interface i/f to applications. By this, applications may acquire network resources via this interface in an abstracted way, e.g. “connectivity between topological point A and topological point B with a given bandwidth”. SDN controllers may then instruct NEs out of a pool of NEs where as there might be several options to solve the request—still hiding the network HW to the application by using this abstract interface.
Current mobile network architectures are very complex in terms of transport layering and packet processing of the user payload. Depending of the generation of a mobile network, in an end-to-end connection, transport layers 1 (physical) to 3 or 4 (IP) are affected and require deep per-packet handling over various layers at certain topological points in the network like e.g. gateways. Such comprehensive packet processing not only requires high processing power, but also is difficult to be realized for wire speed, which requires that all packet manipulations are executed in hardware.
Furthermore, mobility management, especially handover between radio access points, add additional complexity as control protocols and anchor to anchor communication are necessary to re-adjust the encapsulation for forwarding
And finally, in order to handle user-to-service and user to domain (e.g. enterprise) contexts, more and more tunneling layers have to be employed to ensure isolation, charging, QoS and security. This results in that—typically in an end-to-end user-to-service connection—various tunnels requiring various stateful interworking must be employed, e.g. a GTP tunnel (P-Gw—S-Gw—eNodeB), an IP tunnel (with an “outer” IP address), a VLAN tunnel and VPN tunnel (for security). This architecture makes it very difficult to do frequent changes in the network deployment since a variety of nodes requires complex (re-)configuration when adding/removing equipment.
Furthermore, during the course of mobile network evolution, more and more complex functions where added to specific nodes, like e.g. a P-GW or a GGSN, respectively, where control plane functions (C-plane) and data forwarding functions (U-plane) are closely mingled—which makes it more and more difficult to cope with ever increasing traffic, as the forwarding of each packets requires a high number of processing steps
As a further drawback of today's architectures, there are two trends in IT and telecommunications that bring the existing architecture of RAN backhaul and core transport/core network to its limits:                1) Virtualization: there is a strong trend to de-compose core network functions and have them run as applications in data centers. This allows for HW independency and network elasticity. However, some of the core network nodes (e.g. gateways) show such a deep C-/U-Plane interworking that simple virtualization would mean that all traffic will hit the cloud. Here an architectural simplification of the end-to-end interconnection will be inevitable.        2) Localization in 5G: In the fore field of new emerging 5G architectures, it becomes obvious that much of the functionality that is currently done in the core network will be handled locally, in LAN based environments with a mix of WLAN access and pico/femto LTE base stations.        
Here an architectural approach based on LAN technologies—most beneficially combined with mobile network principles—will be required.